diff --git a/Lib/curses/textpad.py b/Lib/curses/textpad.py
index 28d78dd5cd3..120c5721ee7 100644
--- a/Lib/curses/textpad.py
+++ b/Lib/curses/textpad.py
@@ -53,7 +53,7 @@ def _end_of_line(self, y):
         last = self.maxx
         while 1:
             if ascii.ascii(self.win.inch(y, last)) != ascii.SP:
-                last = last + 1
+                last = min(self.maxx, last+1)
                 break
             elif last == 0:
                 break